| Theron W. Mortimer | |
| Birth Date: | 27 May 1872 |
| Birth Place: | Minburn, Iowa, U.S. |
| Death Place: | Los Angeles County, California, U.S. |
| Player Years1: | 1896–1899 |
| Player Team1: | Chicago |
| Player Positions: | Tackle |
| Coach Sport1: | Football |
| Coach Years2: | 1900 |
| Coach Team2: | Colorado |
| Coach Years3: | 1901 |
| Coach Team3: | Alma |
| Coach Sport4: | Baseball |
| Coach Years5: | 1900 |
| Coach Team5: | Colorado |
| Overall Record: | 9–6 (football) 4–2 (baseball) |
Theron Winifred "T. C." Mortimer (May 27, 1872 – October 1, 1952) was an American football player and coach of football and baseball. He served as the head football coach at the University of Colorado at Boulder in 1900 and at Alma College in 1901, compiling a career college football record of 9–6. Mortimer was also the head baseball coach at Colorado in 1900, tallying a mark of 4–2. Mortimer graduated from Simpson College in 1896 and played football as a tackle at the University of Chicago from 1896 to 1899.[1]